Limit flame phenomena, e.g. ignition, extinction and change in flame stabilities, are important combustion features that can significantly affect fuel efficiency, engine safety, and pollutant emissions. Systematic detection and modeling of limit phenomena in large-scale flow simulations can be highly challenging due to the lack of algorithms for efficient and rigorous data mining in large flame datasets. Computational flame diagnostics (CFLD) are systematic tools to extract salient information from simulated flames, particularly when detailed chemical kinetic mechanisms are involved. The results of CFLD can be employed for various purposes, e.g. to simplify and refine detailed chemical kinetics, and to explain flame behaviors associated with complex chemical kinetics. In the present study, the utility of a recently developed method of chemical explosive mode analysis (CEMA) and a bifurcation analysis (BA) will be demonstrated with a variety of flames involving ignition and extinction, premixed and non-premixed flames, and laminar and turbulent flows. CEMA will be utilized to analyze datasets from recent direct numerical simulations (DNS) of homogeneous charge compression ignition (HCCI) combustion, lifted jet flames, and non-premixed jet flames. Chemistry-flow interactions in flames involving limit phenomena will be further explained by CEMA and BA.

Bio

Dr. Lu received his B.S. and M.S. in Engineering Mechanics from Tsinghua University in 1994 and 1997, respectively, and Ph.D in Mechanical and Aerospace Engineering from Princeton University in 2004. Since then he has been a postdoctoral fellow and a research staff at Princeton. He joined the Department of Mechanical Engineering in the University of Connecticut as an Assistant Professor in 2008. Lu’s primary research interest is in combustion and computational fluid dynamics with special interests in chemical kinetics and computational flame diagnostics. He is a member of the Combustion Institute, a senior member of the American Institute of Aeronautics and Astronautics, and the recipient of the inaugural Irvin Glassman young investigator award from the Eastern States Section of the Combustion Institute.